Antirachitically active product



Patented Aug. 23, 1938 l UNITED STATES PATENT OFF ICE ANTIRACHITICALLY ACTIVE PRODUCT Adolf Windaus, Gottingen, Germany, assignor to Winthrop Chemical Company, Inc., New York, N. Y., a corporation of New York No Drawing. Application March 19, 1937, Se-

11'i9a3l3 No. 131,779. In Germany December 9.

2 Claims. (01. 260-397) This invention relates to antirachitically actiand the like. The esters of the 22,23-dihydrovated 22,23-dihydroergosterol. ergosterol are saponifled prior to the irradiation In my copending application for Letters Patent or after the irradiation; As esters of 22,23-dihy- Serial No. 131,778 of even date, which, same as this droergosterol first of all those of the lower fatty 5 applicationisacontinuation in part application of acids, preferably the acetic acid ester, but also, 5

Serial No. 755,840, filed Dec. 3, 1934, I have defor instance, benzoic acid ester come into conscribed a process of manufacturing 22,23-dihydrosideration. ergosterol. According to my present invention this The 22,23-dihydroergosterol is transformed by 22,23-dihydroergosterol, contrary to other dihythe irradiation into a colorless resin which is drogenated ergosterols, is converted into an anti insoluble in water but dissolves in the usual .or- 10 rachitically highly active transformation product ganic solvents, such as alcohols, acetone and by chemically active irradiation, particularly by liquid hydrocarbons. The antirachitic activity ultra violet irradiationv This is the more surof the transformation product amounts to one prising since 22,23-dihydroergosterol is the first international vitamin D rat unit in about 0.5-1 7.

l5 transformation product of ergosterol and of sterol Experiments to obtain from the resinous transcompounds at all which has been obtained by a formation product a crystalline substance have chemical process other than an irradiation procnot been successful when using the usual recryses. and which has the property of being a protallization methods. But I have found that convitamin of an antirachitic vitamin D. My new siderable purification of the product is obtained discovery is further a proof that there are difby transforming the irradiation product into its ferent products having antirachitic activity, for ester, preferably into its meta-dinitrobenzoic the new antirachitic vitamin obtained by irraacid ester. The said ester has been obtained in diation of 22,23-dihydroergosterol not only difa crystalline form. By saponification thereof fers from vitamin D2 prepared by irradiation of and recrystallization of the saponification prodergosterol as to its chemical and physical propuct the antirachitically active transformation 25 erties, but also as to its antirachitic properties, product of 22,23-dihydroergosterol has been obsince one rat unit of the vitamin prepared from tained in a crystalline form. Advantageously 22,23-dihydroergosterol is about times more prior to the esterification step unchanged 22,23- active in the treatment of leg weakness of dihydroergosterol which is still present in the 30 chicken than one rat unit of vitamin D2 prepared irradiation product is removed by the addition 30 from ergosterol. Accordingly, the antirachitic of an alcoholic solution of digitonin. Only the properties of irradiated 22,23-dihydroergosterol unchanged 22,23-dihydroergosterol forms a difare more similar to the antirachitic properties flcultly soluble addition compound with digitonin, of the natural vitamin D principle contained in so that the more soluble transformation product cod liver oil since it is known that the natural can readily be separated from unchanged start- 35 vitamin D of cod liver oil is more active with ing material. Furthermore, it may be advanchicken than vitamin D2 obtained from ergosterol tageous to subject the antirachitically active when equal rat uni-ts of the said products are adtransformation product to a further purification ministered to chicken. The antirachitically acstep by treatment of the irradiation product with tivated 22,23-dihydroergosterol is the first artian ethylene-cis-dicarboxylic acid anhydride, such 40 ficially prepared vitamin D which is clearly difas maleic acid anhydride and citraconic acid anferentiated from the only artificial vitamin D hydride. On prolonged treatment, for instance, hitherto prepared, that is vitamin D2 prepared with citraconic acid anhydride at normal temfrom ergosterol, since the known vitamin D1 is perature only antirachitically inactive by-prodmerely an addition compound of vitamin D2 and ucts react with the citraconic acid anhydride. 45 the inactive lumisterol. When treating the reaction mixture thus obtain- In accordance with the present invention able with saponifying agents, for instance, with 22,23'-dihydroergosterol or its esters are antialcoholic alkali lyes, the active product may be rachitically activated by ultra violet irradiation separated from the salts of the addition com in the usual manner, for instance, by means of a pounds thus formed by extraction with organic 50 quartz mercury vapor lamp or a magnesium solvents, such as ether, petroleum ether or mixspark. The said substances are preferably distures thereof. On esterification of the active subsolved prior to the irradiation in a suitable orstance thus obtainable by means of meta-dinitroganic solvent, such as ether or liquid hydrocarbenzoylchloride yellowish needles of the meta-- 5 bons, for instance, benzine, ligroin, n-pent'ane, dinitrobenzoic acid ester of the antirachitically gactive irradiation product r 22,23-dihydroergosterol are obtained.- They melt at 135-136 C. 1 and have a specific rotary power in acetone solution. The ester has the formula: CasHuNi-Oa. This ester yields on saponification with dilute alcoholic alkali lye a saponification product which on recrystallization is obtained in leaflet-like crystals melting at 107-108" C. Their absorption spectrum has a characteristic maximum at 265 m which is similar to that of vitamin D1; The specific rotary power of the 5 crystalline product is [a +s9.a

According to analysis the crystalline product has the formula 020K400. One international unit of antirachitic activity is contained in less than 0.1

when irradiating 22,23-dihydroergosteryl esters, for instance, 22,23-dihydroergosteryl acetate, esters of the antirachitically active trans formation product of 22,23-dihydroergosterol are obtained which may be saponified and purified J as indicated above.

, The invention is further illustrated by the I following example:

Ezample.--An about 1% solution of 22,23-dihydroergosterol in n-heptane is irradiated in a quartz vessel with the light of the magnesium spark while excluding oxygen. At a distance of about 5 cm. the irradiation is continued during about 4 hours. After the solvent has been removed under reduced pressure, an amorphous colorless resin remains. Its antirachitic activity amounts to one international vitamin, D rat unit in 0.5 to 1 -y. g

Instead of the. magnesium spark the usual quartz mercury vapor lamps may be used as the sources of ultra violet light. Instead. of nheptane other solvents, for instance, benzine and llgroin, benzene, the lower alcohols or mixtures thereof may be used.

The antirachitically active resinous product is transformed into a crystalline product of increased activity in the following manner:

7 grams of the resinous irradiation product are treated with 100 ccs. of methanol which is free from air at 3540 C. Then an alcoholic solution of 10 grams of digitonin is added. The mixture is evaporated to dryness under reduced pressure. The residue is treated with about 150 ccs. of low boiling petroleum ether, thoroughly shaken therewith and left standing at ordinary temperature for 12 hours. 22,23-dihydroergosterol-digitonide and excess digitonin remain undissolved; they are filtered and washed several times with petroleum ether. The filtrate is evaporated to about 10 ccs. and treated with a solution of 3 ccs. of citraconic acid anhydride in absolute peroxide-free ether; just such a quantity .of ether isused for this purpose that the citraconic acid anhydride is clearly dissolved in the ether-petroleum ether mixture. The solution is then left standing for 5 days with careful exclusion of air. After that time the 22,23-dihydro-tachysterol has completelyfreacted with I the citraconic acidanhydride. The solution is then evaporated to dryness at 35-40" C. under reduced pressure and the residue dissolved in about ccs. of methylalccholic potash lye. For complete saponification the solution is left standing for 12 hours. It is then treated with the double volume of boiled water and several times extracted with a mixture of petroleum etherether. The petroleum ether-ether solution is shaken with air-free water, dried with sodium .sulfate, filtered and evaporated. A yellowish colored oil remains as the residue which after thoroughly dryingis dissolved in a small quantity of pyridine. The mixture is then treated with a solution of 3 grams of meta-dinitrobenzoyl-chloride in a small quantity of pyridine. After 12 hours standing the weakly brown colored solution is poured into water which is saturated with sodium bicarbonate. The oily product precipitating therefrom is taken up in ether. The ethereal solution is several times shaken with water, dried over sodium sulfate and evaporated to dryness under reduced pressure. A brown colored oil remains which is repeatedly extracted with hot methanol. The methylalcoholic extracts are united and evaporated in an exsiccator which is filled with carbon dioxide. The solution is poured off from the. oil first separated. The process is repeated several, times until finally thin, needle-like crystals separate l s'= +94-5 A solution of 1.5 g. of the meta-dinitrobenzoate in 30 ccs. of 5% methylalcoholic potash solution is boiled for about 20 minutes on the waterbath in a current of nitrogen. The potassium salt of the meta-dinitrobenzoic acid precipitating is filtered and the filtrate carefully mixed with water. From the solution thin, leaflet-like crystals separate after short standing which after filtering are washed with aqueous methanol.

They are repeatedly redissolved from acetone with theaddition of a small quantity of water. Acetone containing water is used as the washing liquid.' The white crystals melt at 107-108 C. Their absorption spectrum, same as that of vitamin D: has a characteristic maximum at 265 m; the absorption coei'licient is likewise the same as that of vitamin D1. The analysis has the formula: CaHuQ- The specific rotary power is I claim:

1. The antirachitically active product obtained by ultra violet irradiation of 22,23-dihydroergosterol.

2. The crystalline antirachitically active product obtained by ultra violet irradiation voi' 22,23- dihydroergosterol, which product has the formula Cal-I400, which melts at 107-108 0., has a ADOLF WINDAUS. 

